When ultrarunner Ronda Sundermeier started feeling sluggish during her usual tempo runs, she wasn't sure what was wrong—she hadn't changed her training. Then she met a nutritionist, who spotted the problem: Sundermeier wasn't eating enough postworkout for her body to recover.

So she started drinking a carb-and-protein recovery shake immediately after her run, and then made sure to sit down to a full meal within 45 minutes. "The results were phenomenal," Sundermeier says. "Suddenly, I felt like I was on fire during the hardest parts of my workouts."

Most runners know that they need to eat a combination of healthy carbs and protein soon after a workout. But Sundermeier's experience proves that there are different kinds of postrun scenarios, each with its own nutritional challenges and requirements. After all, an easy evening three-miler doesn't require the same refueling strategy as a tough 14-mile tempo run. "Your body needs nutrients to build muscle and gain fitness, but it's not always clear when, what, and how much you should eat," says Deborah Shulman, Ph.D., a sports nutritionist in Colorado.

The right meal at the right time makes a big difference. After revamping her nutrition, Sundermeier broke the course record at the Grand Teton 100-Mile Ultramarathon. Here's how to tailor your meals for five common postrun situations.

Postrun: You're starving after a three-miler.

Eat This: After an easy, short run, you haven't burned a ton of calories or worked your muscles extremely hard, so usually there's no need to eat much. "But if you're really hungry," says Shulman, "it's a signal your carbohydrate levels are low and you started the run depleted." To satisfy your belly without going overboard on calories, Amy Jamieson-Petonic, R.D., a spokesperson for the American Dietetic Association, suggests high-fiber foods. Many studies, including a large review done by researchers at Tufts University, have shown fiber helps people feel fuller and more satisfied. "Try a whole-wheat bagel or a handful of dried figs," she says. Stomach still growling? Eat a little bit of fat, like a few nuts or an egg, to satisfy your appetite, says Molly Kimball, R.D., a sports dietitian at the Elmwood Fitness Center in New Orleans.

Postrun: After a 45-minute run, you're short on time.

Eat This: For many runners, this type of workout is the backbone of their training, especially on time-crunched weekdays. For runs less than 60 minutes, don't worry about getting exactly the right ratio of carbs-to-protein postrun; rather, focus on eating foods that contain both. "It's when you run over an hour that the carbs-to-protein ratio becomes more important," says Jamieson-Petonic. Just aim for healthy choices. If you run in the morning, freeze a fruit and yogurt smoothie the night before and take it out to defrost before your run. If you're a noontime runner, pack a hummus and veggie pita sandwich to eat after you get back to your desk. Need a quick dinner after an evening run? Keep your freezer stocked with single, frozen chicken breasts or salmon fillets and pair with fast-cooking brown rice and steamed asparagus.

Postrun: You ran long and hard, and you're tired.

Eat This: When you run longer than an hour, you need to focus on refueling—and fast. "There's a 30-minute window where the body is very receptive to getting carbs back into the muscles," says Shulman. To know your carb needs, divide your weight in half. If you weigh 140 pounds, you need 70 grams (280 calories) of simple carbs within 30 minutes. Try energy bars or sports drinks because they're quickly absorbed. Getting some protein, too, will kick-start muscle repair. Within an hour of that snack, eat a full meal, ideally in a 4:1 carbs-to-protein ratio. According to a 2006 study in Medicine and Science in Sports and Exercise, eating carbs and protein together increases glycogen levels more than eating just carbs. Try a bean burrito or pasta with meat sauce to give your body the nutrients it needs, says Shulman.

Postrun: You feel queasy.

Eat This: If your stomach feels upset after a run, it's likely telling you it's been stressed out—either by dehydration, too many gels, or from working hard to get fuel into your system. Even though you might not feel like eating, doing so will help reduce that unsettled feeling and speed recovery. Skip energy gels and chews, which are digested very quickly, says Shulman, and "choose something that takes longer to break down, such as a banana or crackers and cheese—they'll stay in the stomach longer, protecting the lining from acid and helping override that queasy feeling." Other ideas? Jamieson-Petonic suggests ginger tea with sugar, while Kimball likes bland, easily digestible carbs, such as Cream of Wheat.

Postrun: You ran at night, and bedtime looms.

Eat This: Since you'll be going to bed soon, you don't want to eat too much. Doing so regularly could lead to indigestion—and weight gain. One way to prevent overeating after a late run is to "have your last real meal about two hours before your run," says Shulman. After your workout, you won't be superhungry and can refuel with something easy to digest. Jamieson-Petonic suggests sticking with a mix of carbs and protein, like graham crackers with peanut butter and a bowl of berries. Not only will it take the edge off if you're a little hungry, but "the carbs will replenish glycogen stores overnight and the protein will start healing your muscles," says Jamieson-Petonic, so you'll be ready to run again the next day.

This Just In

PB AlertSalmonella found in PB produced by the Peanut Corporation of America prompted Clif Bar, Luna Bar, Larabar, and other companies to recall many peanut butter-flavored bars. To see if you need to toss yours, go to fda.gov.

Okay ChardonnayAccording to a study in the October 2008 Journal of Agricultural and Food Chemistry, researchers found that white wine contains two antioxidant compounds that may give it the same heart-protective qualities as red wine.

Run Off HungerIn a 2008 study, British researchers reported that aerobic exercise reduced participants' self-reported hunger levels and affected hormones that suppress appetite more than either weight training or no exercise.

More Pasta, PleaseIn a December 2008 study, researchers had cyclists keep a food log for three days prior to a race. While 57 percent of the cyclists reported carbo-loading, only 23 percent actually consumed high enough levels of carbs.